This invention in part, relates to well drilling and completion devices and processes. More specifically, the invention, in part, is concerned with providing devices and methods that improve the ability to azimuthally orient perforating devices away from downhole cables within a perforating zone.
Conventional wells and well completions typically provide little or no downhole instrumentation and/or fluid control capability. Some conventional well completion procedures are relatively simple, essentially running production or injection tubing into the well along with perforating, gravel packing, and/or logging steps as needed. Pressure and flow control in conventional oil, gas or other fluid-producing wells typically use valves and instruments located at or near the surface in a Christmas tree arrangement. Formation fluids are typically produced until a downhole problem occurs, e.g., reservoir pressure declines or the water-cut increases or something else happens downhole that significantly reduces production or prevents the well from further commercial operation.
To evaluate the cause of production or injection problems in a conventional well, the well is typically taken off-line and one or more logging tools supported by a wireline are run through the tubing within the well. The logging tools may be used to check downhole fluid pressures, fluid types, zonal flowrates or other parameters at one or more depths to try to determine the cause of the production or injection decline and the corrective action needed. Once the problem is determined and/or new production or injection zones identified, the wireline tools are typically removed and a second re-entry into the off-line well is accomplished to correct the problem, e.g., using a workover rig. For example, a second re-entry might lower a perforating tool to re-perforate/re-complete the well at a new producing level. These conventional well completions, re-entries, and re-completions may consume unacceptable lost production time and costs, especially when applied to deepwater, multi-producing zone, high temperature, and/or high-pressure reservoirs and wells.
In contrast to conventional wells and well systems, the term “intelligent” and “smart” wells and well systems may refer to wells having downhole process control, instrumentation, and/or related components. Other terms used for intelligent or smart well systems include SCRAMS (Surface Controlled Analysis and Management System), IRIS (Intelligent Remote Implementation System), and RMC (Reservoir Monitoring & Control).
But no matter what these well systems are called, they enable real-time downhole operation, surveillance, data interpretation, intervention, and/or process control in a continuous feedback loop. The smart wells allow problems to be detected and possibly minimized or corrected without taking the well off-line. Smart well systems can therefore operate for long periods without the need to shut down and introduce instrumentation or additional wireline tools. However, the introduction of perforating tools is still typically required during the less frequent workover processes.
A smart well system typically uses downhole tubing, cables or other means for transmitting power, real-time data or control signals to or from surface equipment and downhole devices such as transducers and control valves. Power and signals typically use transmission means such as electric and/or fiber optic cables, but other transmission devices can include fluid tubing.
Other well applications may also have cables or other transmission means present during operations that may include perforating. Other well processes and applications that may require downhole transmission means include wells having a submersible electric pump, measurement while drilling (MWD) methods, and the use of downhole directional & inclination indicators, hydraulic actuators, and power supplies, e.g., for data transmission using mud pulse telemetry.
Perforating or re-perforating a well having a downhole cable or other transmission device must avoid damaging the transmission device during the perforating process, typically requiring a step of azimuthally orienting a directional-perforating device. The orienting step directs the perforating action away from nearby cables or other devices in the well. Orientating methods may include magnetic oriented techniques (MOT), obtaining positional data from downhole probes, using gravity-actuated orienting devices for non-vertical boreholes, limiting operations to within guided downhole paths, obtaining orienting data from gyroscopes, and using mechanical indicators or orientation subs.
However, the orienting step can add significant cost and/or present feasibility problems, especially when high temperature, corrosive fluids, high pressures, multiple completion zones, or other difficult downhole conditions are encountered. The added costs and problems can also be compounded by the added time to accomplish the orienting step for deep offshore wells. For example, application of current MOT techniques may be limited by high downhole temperatures and since typical well depths have been increasing, increasing downhole temperature problems for MOT processes may be encountered.